1. 21
copper cabling systems SPECIAL FEATURE
T
he volume of electronic data is
rocketing. Every minute YouTube
users upload 72 hours of new
video, over 200 million emails are
sent and Twitterers Tweet 300,000
times. Alongside social media, the
use of smartphones, the evolution
in industrial sensors, the proliferation
of CCTV and the growth of video on
demand and cloud computing have all
contributed to an explosion in data.
Added pressure
With these increased volumes comes
increased pressure on data centres and,
in particular, the challenge of providing
data centre infrastructure capacity
without a degradation of service. In
response, cabling standards are evolving
in an attempt to keep pace with the
increasing capacity demands.
In July 2012, industry representatives
decided that a copper cable capable
of handling 40Gb/s of data was worth
developing. Now, less than three years
after that declaration, a Category 8,
40Gb copper twisted pair cable has
been launched as part of the Universal
Cabling (UC) Connect System.
The new Category 8 screened
foiled twisted pair cable is available in
two options – an installation cable and
a patch cable. The installation cable
has an outside diameter of 8.5mm and
an installed bending radius of 68mm,
while the patch cable is thinner with an
outside diameter of 6.0mm and a shorter
installed bending radius of 48mm. Both
cable options incorporate four twisted
cable pairs, screened using aluminium
laminated plastic foil; the overall cable
assembly is then encased in a copper
braided tinned screen surrounded
by a low smoke halogen free sheath.
Their construction ensures both
cable types have a data transmission
performance of up to 2GHz, which is
four times the bandwidth of Category
6A cables and with significantly higher
alien crosstalk requirements.
Aftereight
The latest Category 8 cable could be set to transform data centre network infrastructures by
providing a cost effective alternative to fibre optic. Lee Stokes at Draka UC Connect explains.
The adoption of Category 8
cabling in a data centre will
open up fresh possibilities.

2. 22
copper cabling systemsSPECIAL FEATURE
Lee Stokes is product
manager for Universal
Cabling (UC) Connect.
Lee’s role sees him take
responsibility for the
design and development
of new product ranges
for Draka’s rapidly
growing markets in the
UK, Asia and Turkey. In
addition, he will support
the sales teams in each
region with technical
expertise and provide
advice and information
for installers and
consultants.
Lee was previously
involved in the development of the UC Connect System
as business development manager. He joined Draka with
a background as a hands-on engineer who developed his
career into product development, recently holding the role
of product manager.
Alternative
The launch of the 40Gb/s copper cable
will give data centre operators a cost
effective end-to-end alternative to fibre
optic and Twinax solutions, neither of
which are ideal. Twinax solutions are
limited to short distances of 7m while
fibre is expensive – not because there is
a huge difference in the cost of copper
over fibre optic cable but because
fibre optic switches, connectors and
transmitters cost significantly more than
their copper equivalent.
The preferred way of connecting
servers to switches in a data centre has
been Ethernet over twisted pair. Typically,
switch-to-server links are 30m or less.
Since initial 40GBase-T applications will
be limited to data centres, the standard
link length of 100m for a twisted pair
has been deemed not to be essential.
This is significant because for higher
bandwidths copper is clearly limited
in the distance over which it is suitable
before attenuation reduces performance
unacceptably. As such, the IEEE, TIA and
ISO bodies have all accepted a maximum
channel reach of 30m with a maximum of
two connections.
While all main cabling standards
bodies agree on the maximum reach
there is, however, a significant difference
in cable performance between the
different bodies concerning backwards
compatibility. North American standards
body the TIA, for example, has decided
to break with convention so that the
Category 8 product it describes does not
have to be backwards compatible with
Category 7 or Category 7A products.
ISO, on the other hand, has continued
with the backwards compatible
convention so an ISO compliant product
will be backwards compatible with both
Category 7 and Category 7A solutions.
The new Category 8 cable complies
with the ISO/IEC standard and the less
onerous TIA standard.
Further developments
Compliant cable is only one element
of the 40Gb system, however, and
manufacturers of connectors will also
need to develop their products to be 40
GBase-T compatible in order to provide
system solutions. In recommending
the development of 40 GBase-T, the
IEEE indicated its expectation that
RJ-45 connectors would be the chosen
connector technology due to its ease
of use and backwards compatibility.
Some connector manufacturers have
developed high performance non-
standard Category 8 solutions. RJ-45
has been the technology of choice for
IT professionals because of its low cost
and ease of use, largely because of its
backwards compatibility, which will allow
the new technology to integrate with
legacy Base-T applications.
The adoption of Category 8 cabling
in a data centre will open up fresh
possibilities for connectivity and a host
of new data intensive applications.
It will also improve energy efficiency
by reducing the total amount of links
in a data centre and reduce overall
operational expenditure by alleviating the
need to aggregate multiple 10G Base-T
links to achieve 40Gb/s transmission
speed. In fact, experience in developing
twisted pair copper cable solutions for 10
GBase-T Ethernet systems suggests that,
where copper based data systems can be
delivered, the cost advantage will ensure
the development of a viable market for
higher capacity systems. It remains to be
seen if Category 8 will have a use outside
of data centres, but once the advantages
of this capacity become more widely
recognised my feeling is that it may well
end up in office environments.
100Gb/s
Now that a 40Gb copper cabling
solution has been developed the
next step in innovative product
development for the cabling industry
will be to develop the technology to
cope with 100Gb/s transmission speed.
This will be the ultimate challenge
because data volumes this high are
probably approaching the maximum
technical capacity of copper – watch
this space.
It remains to be seen if Category 8 will have a use outside of data centres.